the cost will depend on the size of the dog, so what type do u have?
it cost me about $110 to get our girl fixed, but she's a teeny tiny jack X chawawa(sp?)
i was quoted about $150 for our goldie to get fixed at 6 months old.
But a friend of mine got charged $350 for her cav X maltese, so shop around first

As for her period, it should stop over the next week or so, they can do it as soon as she's finished but there could be a bit of excess bleeding if u do. Thats what happened to our girl, as soon as i booked her in she went on heat! lol
Her loss was more spotting but it was fairly constant and if she slept in one spot for a while there was a nice big red patch.
A good way to tell if she's going to be finishing up soon is her girly bits wont be as swollen
HTH